Bandgap Expansion of a Nanometric Semiconductor

With the miniaturization of a solid, the band gap expands and the energy levels of the core bands shift towards higher binding energy, and subsequently, properties such as dielectrics change. These intriguing phenomena have been found new applications in microelectronics and photonics for devices. However, the underlying mechanism for these phenomena is still under debate. Here we present a new approach showing that the bond contraction at the surface and the rise in the surface-to-volume ratio of the nanosolid are responsible for these phenomena as the spontaneous bond contraction enhances the interatomic binding energy, which results in the corresponding derivatives.